In Brussels, Argentina’s world No.39 Leonardo Mayer beat Steve Darcis 7-6 (7-5) 7-6 (7-1) 4-6 6-3 after David Goffin, the world No.15, had seen off Federico Delbonis 7-5 7-6 (7-3) 6-3 to give Belgium the lead.

Britain are playing in their first semi-final in 34 years and have been without a Davis Cup title since 1936.

Belgium are bidding to reach the final for the first time since 1904 while their last semi-final run before this year was in 1999.

Argentina are also yet to win a Davis Cup, having been runners-up on three occasions.

On Saturday, Ruben Bemelmans and Kimmer Coppejans for the home side will face Carlos Berlocq and Diego Schwartzman in the doubles.

“My opponent left nothing out there,” said Goffin after his win over Delbonis.

“It was a difficult match but I came through in straight sets and I stayed tough mentally.”

Belgium have made the most of a good World Group draw this year.

In the first round, they knocked out defending champions Switzerland who were without Federer and Stan Wawrinka and then saw off Canada, without Milos Raonic, in the quarter-finals.

That opening stage loss forced Switzerland into a play-off but with Federer and Wawrinka back in the line-up, they opened up a 2-0 lead over the Netherlands in Geneva on Friday.

French Open champion Wawrinka toiled to beat Thiemo de Bakker 2-6 6-3 4-6 6-3 7-5 while Federer, just off his US Open final loss to Novak Djokovic, eased past world No.436 Jesse Huta Galung 6-3 6-4 6-3.

“He moves so fast on the court – he’s like a ghost,” said Huta Galung of Federer.

De Bakker was left to regret a dramatic slump against Wawrinka having led 3-0 in the fourth set.

“I lost my head,” admitted de Bakker.

The United States, the 32-time champions but also battling to preserve their World Group status, were 1-1 with Uzbekistan in Tashkent.

The play-offs between India and the Czech Republic, Russia against Italy, Poland and Slovakia and the Dominican Republic against Germany were also all level at 1-1 after the first day.

Meanwhile, former world No.1 and 14-time grand slam title winner Nadal shrugged off his recent struggles to help Spain to a 2-0 lead in their Group One relegation play-off against Denmark.

Nadal was far too good for the world No.909 Mikael Torpegaard, winning 6-4 6-3 6-2.

The 29-year-old hasn’t played a Davis Cup tie since 2013 and the five-time champions have suffered in his absence with three consecutive defeats to Germany, Brazil and Russia propelling them out of the World Group.

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